The present invention relates to a method of sealing and cutting an underground pipeline or the like at or near the point where it connects to a main without the need for excavation. More particularly, the present invention relates to the insertion of a thermally stabilized cross-linked preshrunk polyolefin plug which is inserted into the line and expanded by heating.
There exists a serious, time consuming and expensive problem in the gas utility industry with respect to the cutting off of gas and the removing of gas lines from premises which have been abandoned. Present federal regulations require the gas line to be plugged at or near the main and the gas line cut when a premise has been abandoned for six months or more. The federal regulations are safety regulations in order to prevent explosions and other possible problems caused by the leaking of gas. Federal regulations not only require the plugging of the line, but also the cutting of the line at or near the gas main after it has been plugged so that future excavations by means of heavy equipment will not rip the line from the gas main causing a substantial gas leak.
The cost to the utilities in terms of time and expense to comply with the federal regulations is very substantial. Prior to the present invention, the gas utility would have to excavate at the point where the gas line connects to the main. This is usually in the street or sidewalk. There is substantial expense in the excavation and then the necessary refilling and repaving operations.
The present invention enables the gas line, or any other similar type of line, to be plugged at or near the main and the line to be cut on the side of the plug away from the main, without the need of excavation.